Fluid flow control using boundary layer control

Abstract

A fluid flow control device (210) including an active actuator surface may be used to control boundary layer separation by controllably deforming the actuator surface to create a depression in an exterior face of the surface. Boundary layer control may thus be achieved by producing a turbulent state which is more resistant to separation than the original laminar flow by energising the boundary layer and preventing it from separating. The surface may comprise an electroactive polymer membrane (100) supported on a substrate (200) and a set of electrodes (300, 310) adjacent to a cavity in the substrate. The electrodes may be used to control the deformation of the electroactive polymer membrane to deflect into the cavity and thus create a depression. A fluid flow control system, vehicle, vessel, aircraft or stationary structure employing a fluid flow control device as described above is also envisaged. The fluid flow control device in a method of controlling a fluid flow over surface, including forming one or more depressions in the surface and varying the depths of the depression or depressions as a function of time.